Air purge for water heaters



April 1931. F. 0. WALLENE 1,799,715

AIR PURGE FOR WATER HEATERS Filed Jan. 27, 1928 Patented Apr. 7, 1931 FRANK O. WALLENE, 01: LAKEWOOD, OHIO AIR PURGE FOR WATER HEATERS Application filed January 27, 1928. Serial No. 250,057.

This invention relates to an air purge for withdrawing foul gas and air from steam or other gas or vapor in the process of being condense lVhile the invention is adapted for use in any place where purging is desirable for any purpose, such as in refrigeration, it is possibly more particularly useful in connectionwith feed water heaters or like devices, l where steam or vapor is employed to heat water to be fed to a boiler or to beused for other purposes, one of the chief sources of heat transfer in such heaters being'by direct contact of the steam or vapor with the surface of the water.

The present invention has for its object to provide apparatus of this kind by which 7 steam or other Vapor or gas may be purged of any air or heat insulating gas which may be entrained therewith and prevent the same from forming a blanket stratum lying on top of the liquid and thereby preventing eflicient transfer of heat. I

In the drawings, Fig. 1 represents a longitudinal sectional elevation, more or less diagrammatic, of one simple arrangement embodying the invention; Fig. 2 is a sectional plan view on the line 22, Fig. 1; Fig. 3 is a detail view in diagrammatic form, illus trating one suitable valve controllingmechanism; and Fig. 4 is a view corresponding to Fig. 2 and showing a modification.

For convenience, but without any thought of limitation, the invention will first be described with reference to its usein connection with steam and water, as in feed water heaters and the like. v

1 indicates the casing or jacket of a conventional feed water heater provided with a valve controlled steam inlet 2, a steam outlet 3 andan outlet pipe 4 by which the heated water is conducted to the place of use. The water inlet is by way of a pipe 5 controlled by a valve 6 connected to the supply line 7, said valve being arranged to open by the effect of a weight 8 on the lever 9 connected to the valve stem, the other end of the lever being connected by a rod 10 to an arm 11 on a shaft 12 passing through a packing 13 in the casing wall, and on its inner end provided with an arm 14 carrying a float 15. Fall and rise of the float open and close valve 6. This arrangement is the usual flush valve water sup ply mechanism adapted to maintain the water in the casing at a definite predetermined level.

In these feed water heaters the water supply is usually conducted over baffles to expose it to intimate contact with the steam in the chamber 16, and the system may be provided with filtering means and the like, but none of these devices have been shown. A large share of the heat transfer from the steam or vapor 'to the water occurs by surface contact. Be-

cause water always contains some air, and for other reasons, the exhaust steam supplied to the heater gradually gathers in the cham ber 16 all of the entrained air and gas, which is heavier than the steam or vapor and therefore collects on the surface of the water in a layer or stratum gradually increasing in thickness and forming an increasingly effective heat insulating blanket. As a result, it has been found in practice that these feed water heaters and like devices become airbound to the extent that exhaust steam at a pressure of say ten pounds and a temperature of about 235 F. will heat the water to not more than say- 72 if the system is air-bound, whereas, if the system is purged or free of air, one-half pound of steam pressure will P1 produce feed water at a temperature of nearly 212.

According to the present invention, I provide means sensitive to the temperature of the water or ofthe. gaseous zone or stratum just above the Water level where the air or gas gathers and arranged so that when the temperature of said zone falls below a predetermined minimum the chamber above the water'will be'purged by the withdrawal therefrom of any air or other heat insulating gas.

In the arrangement shown in Fig. l the arm 14 is in the form of a tube supported by the float with its inlet 14a just above the water level and preferably covered with an anti-splash baffle 17 The shaft 12 is also hollow, and outside of the casing passes through a sleeve 18 so that it can rotate therein, its channel or opening communicating with a valve '19, shown for purposes of'illustra-tion ;passages in pipes 14, 12, etc.

as of the solenoid actuated type. This valve may be actuated manually but it may also be subjected to the effect of the temperature in the zone before mentioned, such as by being provided with an actuating coil 20 in a circuit 21 including a source of current 22 and a normally open switch 23, the contacts of which are actuated by an expanding and contracting bellows 2st, the chamber in which communicates by a tube 25 with a bulb or cartridge 26 suitably located for me purpose. In Fig. 1 this bulb or cartridge is shown as located in the zone just above the water level, where the heavier air or heat insulating gas is gathered or collects below the steam, but, if desired, it may be located be- ..neath the level of the water and there fore directly sub'ect to its temperature, or it can be located in any of the channels or In the latter case, after each purging operation, the steam in said channels and passages condenses .andasair gathers in the stratum or zone before mentioned, it naturally flows by gravity into the channels or passages in the pipes and therefore affects the bulb or cartridge 26 by its temperature. Any of these arrangements is permissible, although the one last described in some cases may be found preferable.

lVit-hthe arrangement described, and as shown for illustration iirFig. 1, the float 15 rises and falls with changes in level of the water and actuates the valve 6 to control the water supply, asis usual. lVhatever be the water level, the inlet 14a always lies in the zone just above it, wheretho cartridge 26 is shown. If the chamber16 isfull of steam or vapor andno air or other gas is present, the temperature throughout the chamber will be relatively high. The expansible material in cartridge 26 is expanded. bellows 2% is expanded, and the switch 23 isheld open. Valve 19 is closed. Asv a consequence, steam continues to flow through the chamber 16 to the outlet 3 and heated water may be withdrawn from pipe 4:, as is usual. However, when, in the course of time, air or gathers in the zone just above the water level, the temperature of said zone and at the bulb or cartridge 26 falls, with consequent contraction of the bellows 24-. The parts are set so that when the teniperature fallsto a predetermined minimum, switch 23 closes. thereby energizing coil 20 and opening valve 19. As a. consequence, steam begins to pass through the inlet 14a and by way of pipe 14, shaft 12 and valve 19 to the outletpipe 27, from whichit is discharged into theiair or to a sewer. The flow continuesuuntil the charm her-1G is completely evacuated of all air or other heat insulating gas: and becomes filled with new steam,whereupon the temperature at the cartridge 26 rises and causes bellows 24 .toexpand, openingswitch E23 and permitting valve 19 to close and shut off the out fiov;

-Fig. 4, where thefloat 15 is on an arm 14 turning a shaft 12 having an arm 11 adapted to actuate the water supply valve, and the purging means includes another float 30 on tubular arm 31 through which steam flows to the. pipe 32 and thence througha controlling valve 19 to atmosphere, as before.

.lVhile the invention has been so far .described as to its application forfeed water heaters and in like uses of steam and water, 5%

it is also capable of use in the refrigerating art, where a suitable refrigerant,.such as am- .111011121, is compressed and delivered to a condenser where its heat is absorbed by a cooling! agent, such aswater, the liquefied refrigerant being delivered to receivers from which it is withdrawn for the refrigerating effect. Such systems sometimes become air-bound and ineffective bygradually gathering air or other gas heavier than the gaseous refrigerantand entrained with the refrigerant either in'the original. charge or by inward leaks,

and such air gathers at the lowest point, usually 1n the recelvers, and creeps up until it finally begins to gather in the condenser and may fill the. same to the extent of very materially reducing the area for available heat transfer from the compressedrefrigerating gas to.the cooling water. It is desirable.

therefore, to purge suchsystems of the air or like gas, and because it always collects above the surface of the liquefied refrigerant, such systems maybe provided with purging means of the kind described above, to wit, anoutlet or discharge system including the necessary' pipes and channels leading to the outside air, the inlet to the purging system being supported by a float or otherwiseso that it lies close to the upper surface of the refrigerating liquid and therefore at the lowest gas level in the condensing system. The discharge valve may here be actuated automatically by some suitable variation in conditions, such as a variation in temperature or pressure, butusually it is a hand actuated valvewhich can be opened whenever variation in some condition in the plant gives notice of lack of eiiiciency. The air or other objectionablegas is withdrawn until refrigerating gas-issues, when the valve is closed. Such a purging system always withdraws the objectionable gasfrom-a level just above the liquid.

lVhat I claim is:

1. Purging apparatus includmg a cham- .'ber for containing steam-and water, means for supplying steam to said chamber, and means sensitive to variations in the temperature of the water for withdrawing of air or other heat insulating medium from a zone slightly above the water surface.

2. Apparatus of the kind described, comprising a chamber for containing water, means for supplying steam thereto, and means sensitive to the temperature of the gas zone closely neighboring the surface of the water in said chamber for withdrawing gas from said zone upon reduction in temperature thereof.

3. Apparatus of the kind described, comprising a chamber for containing Water to be heated, means for supplying heating steam thereto, a valve controlled outlet from said chamber communicating with said chamber in a zone just above the surface of the water therein, and means for opening said outlet gpon reduction in temperature in said chamat. Purging apparatus, comprising a chamber adapted to contain gas and liquid, purging means including a variable discharge pipe from a gas zone closely neighboring the gas and liquid contact surface, and temperature responsive means for controlling said purging means.

5. Apparatus of the character described in claim 4, in which said purging means is unaifected by variations in level of the gas and liquid contact surface.

6. Purging apparatus, including a chamher for containing liquid and gas, a discharge conduit having its inner end open to the gas space and closed to the liquid space in said chambenmeans eflective during the variations in liquid level for maintaining the open end of said conduit slightly above the surface of the liquid in said chamber, and valve means for controlling outward flow through said conduit.

In testimony whereof I hereby afiix my signature.

FRANK O. WALLENE. 

